Abstract The collecting energy from solar radiation using phase change materials is significant in the field of thermal storage. In the current work, a novel MWCNT-modified hydrate salt/poly (acrylate sodium) copolymer hydrogel (MWCNT-GS/PAAS) form-stable composite PCM was well prepared using mechanical mixing method. The form-stable ability, microstructure, heat storage capacity, thermal stability and thermal-cycling reliability of the prepared MWCNT-GS/PAAS were investigated. The leakage experiment exhibited that the MWCNT-GS/PAAS containing 7 wt% PAAS can maintain original gel-structure without leakage in melting state of hydrate salt. Moreover, scanning electron microscopy was used to demonstrate that the hydrate salt PCM was coated with densified hydrogel film. ATR-FTIR and Raman spectra results indicated that the hydrate salt PCM was encapsulated successfully within the network gel-structure. Differential scanning calorimetry (DSC) suggested that the MWCNT-GS/PAAS composite possessed good thermal storage capacity, of which the latent heat reached up to 187.2 J/g. Thermal gravimetric analysis (TGA) indicated that the retention ratio of the crystal water in MWCNT-GS/PAAS is as high as 64.8 wt% at the temperature where the Glauber's salt completely dehydrated. The heat transfer performance suggested that the thermal conductivity and thermal diffusivity of the MWCNT-GS/PAAS composite increased by 141.7% and 167.1% compared with those of the pure GS. Furthermore, being subjected to 500 thermal cycles, the prepared composite maintained favorable thermal and chemical stability. The obtained results indicated MWCNT-GS/PAAS composite was an outstanding candidate used for solar energy storage systems.

中文翻译：

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通过掺入羟基碳纳米管提高水合物盐/聚（丙烯酸钠）共聚物水凝胶作为形状稳定相变材料的热性能

摘要 利用相变材料从太阳辐射中收集能量在蓄热领域具有重要意义。在目前的工作中，采用机械混合方法制备了一种新型 MWCNT 改性的水合物盐/聚（丙烯酸钠）共聚物水凝胶（MWCNT-GS/PAAS）形式稳定的复合 PCM。研究了制备的 MWCNT-GS/PAAS 的形状稳定能力、微观结构、蓄热能力、热稳定性和热循环可靠性。渗漏实验表明，含有 7 wt% PAAS 的 MWCNT-GS/PAAS 在水合物盐熔融状态下可以保持原有的凝胶结构而不会渗漏。此外，扫描电子显微镜被用来证明水合物盐 PCM 被致密的水凝胶膜包覆。ATR-FTIR 和拉曼光谱结果表明水合物盐 PCM 成功地封装在网络凝胶结构内。差示扫描量热法 (DSC) 表明 MWCNT-GS/PAAS 复合材料具有良好的蓄热能力，其潜热高达 187.2 J/g。热重分析(TGA)表明，在芒硝完全脱水的温度下，MWCNT-GS/PAAS中结晶水的保留率高达64.8 wt%。传热性能表明，与纯GS相比，MWCNT-GS/PAAS复合材料的热导率和热扩散率分别提高了141.7%和167.1%。此外，经过 500 次热循环后，所制备的复合材料仍保持良好的热稳定性和化学稳定性。